Effect of high‐pressure microfluidization on the structure of cassava starch granule

Abstract

Microfluidization has been applied to modify starch granules. The study was conducted to investigate the effect of microfluidization on the structure and thermal properties of cassava starch–water suspension (20% w/w). The means of optical microscopy, SEM, FTIR spectroscopy, XRD, and DSC were applied to analyze the changes in microstructure, crystallinity, and thermal property. Microscopy observations revealed that native starch granules were oval, round, and truncated in shape. After the microfluidization treatment, a bigger starch granule was partially gelatinized, and a gel‐like structure was formed on a granular surface. No significant difference in XRD patterns of the samples were observed and all samples exhibited A‐type allomorph. Crystallinity decreased with the pressure. Sample treated at 150 MPa contains 17.1% crystalline glucan polymer, lower than that of native granules which have crystallinity of about 25.8%. A lower crystallinity means poor order of crystalline glucan polymer structure in starch granules. The disruption of crystalline order within the granule was also observed by FTIR measurement. Thermal analysis using DSC indicated that the microfluidization treatment brought about a significant decrease of melting enthalpy. The gelatinization enthalpy was 12.0 and 3.0 J/g for the native sample and samples treated under the 150 MPa, respectively. The results indicate that high‐pressure microfluidization process induced the gelatinization of cassava starch, which is evaluated by a percentage of the degree of gelatinization, due to a pronounced decrease with increasing microfluidizing pressure.

Effect of high speed jet on the physical properties of tapioca starch

“…Therefore, the partial gelatinization of TS could lead to the increase in particle size due to the presence of aggregates. Similar results were also obtained by Kasemwong et al (2011) who reported that the granule size of cassava starch increased with increasing microfluidization pressure, which may be attribute to the partial gelatinization of cassava starch. Qiu, Li, Chen, Liu, and Yin (2014) also suggested that the particle size distribution curve of homogenized wheat starch granules shifted to a higher value compared to native starch.…”

“…Similar results were also observed with maize amylose and cassava starches (Che et al, 2007;Tu et al, 2013). However, different results were found by Kasemwong et al (2011) who reported that the shapes of cassava starch granules remained unaltered but the originally smooth surfaces of some granules became rough after treated by DHPM.…”

“…Kawai, Fukami, and Yamamoto (2007) revealed that the value of DHgel of potato starch-water mixtures decreased with increased pressure and temperature, while the value of DHretro tended to increase with increase in starch content after treated by high hydrostatic pressure at different temperature (20e70 C). According to Tu et al (2013) and Kasemwong, Ruktanonchai, Srinuanchai, Itthisoponkul, and Sriroth (2011), the mean diameter and gelatinization temperatures of maize amylose and cassava starch decreased with increasing pressure of Dynamic high-pressure microfluidization (DHPM).…”

Effect of dynamic high‐pressure microfluidization on the morphology characteristics and physicochemical properties of maize amylose

“…The smaller the particle is, the greater the aggregation trend is. [30] also reported the granule size of starch was increased with the increase in homogenizing and microfluidization pressure, respectively. The effect of microfluidization is possibly the results of a combination of the disruption of the semicrystalline structure followed by hydration and radial swelling of the starch granules, when the starch-water suspension was put through the microfluidizer [30].…”

“…The results showed that the resistant starch treated with microfluidization contained increased viscosity and water-holding properties. Kasemwong et al [30] studied the effect of microfluidization on the structure and thermal properties of cassava starch-water suspension (20% w/w). The results indicated that DHPM process induced the gelatinization of cassava starch.…”